• Title/Summary/Keyword: TEM/EDS

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Enhanced Electrochemical Property of Surface Modified Li[Co1/3Ni1/3Mn1/3]O2 by ZrFx Coating

  • Yun, Su-Hyun;Park, Yong-Joon
    • Bulletin of the Korean Chemical Society
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    • v.31 no.2
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    • pp.355-359
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    • 2010
  • A $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ cathode was modified by applying a $ZrF_x$ coating. The surface-modified cathodes were characterized by XRD, SEM, EDS, TEM techniques. XRD patterns of $ZrF_x$-coated $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ revealed that the coating did not affect the crystal structure of the parent powder. SEM and TEM images showed that $ZrF_x$ nano-particles were formed as a coating layer, and EDS data confirmed that $ZrF_x$ distributed uniformly on the surface the powder. Capacity retention of coated samples at high C rates was superior to that of pristine sample. However, as the coating concentration increases beyond the optimum concentration, the rate capability was deteriorated. Whereas, as the increase of coating concentration to 2.0 wt %, the cyclic performances of the electrodes under the severe conditions (high cut-off voltage, 4.8 V, and high measurement temperature, $55^{\circ}C$) were improved considerably.

Synthesis of Ru Incorporated TiO2 and Application to Oxidation of Benzyl Alcohol with Molecular Oxygen (Ru를 도입한 TiO2의 합성과 산소를 이용한 알코올 산화반응 연구)

  • Kim, Youngyeong;Choi, Myong Yong;Kwon, Ki-Young
    • Applied Chemistry for Engineering
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    • v.25 no.6
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    • pp.645-647
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    • 2014
  • We synthesized $TiO_2$ ($Ru_x/TiO_2$) incorporating $TiO_2$ and Ru via an one-step hydrothermal method. The physical properties were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The prepared samples were applied as a catalyst for the oxidation of benzyl alcohol to benzaldehyde using molecular oxygen ($O_2$). Especially, the catalytic activities increased as the contents of ruthenium in $TiO_2$ increased without the formation of any byproducts.

Mechanical Properties of ODS Fe Alloys Produced by Mechano-Chemical Cryogenic Milling (극저온 기계화학적 밀링(Mechano-Chemical Milling)에 의해 제조된 ODS Fe 합금의 기계적 특성)

  • Hahn, Sung-In;Hong, Young-Hwan;Hwang, Seung-Joon
    • Journal of the Korean Society for Heat Treatment
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    • v.25 no.3
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    • pp.138-145
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    • 2012
  • An ${\alpha}$-Ferrite (Fe) powder dispersed with 4 vol.% of $Al_2O_3$ was successfully produced by a simple miling at 210 K with a mixture of $Fe_2O_3$, Fe and Al ingredient powders, followed by 2 step high temperature consolidation: Hot Pressing (HP) at 1323 K and then Hot Isostatic Pressing at 1423 K. The microstructure of the consolidated material was characterized by standard metallographic techniques such as XRD (X-ray Diffraction), TEM and STEM-EDS. The results of STEM-EDS analysis showed that the HIPed materials comprised a mixture of pure Fe matrix with a grain size of ~20 nm and $Al_2O_3$ with a bimodal size distribution of extremely fine (~5 nm) and medium size dispersoids (~20 nm). The mechanical properties of the consolidated materials were characterized by compressive test and micro Vickers hardness test at room temperature. The results showed that the yield strength of the ODS (Oxide Dispersion Strengthened) Fe alloy are as much as $674{\pm}39$ MPa and the improvement of the yield strength is attributed to the presence of the fine $Al_2O_3$ dispersoid.

Effect of octadecylamine concentration on adsorption on carbon steel surface

  • Liu, Canshuai;Lin, Genxian;Sun, Yun;Lu, Jundong;Fang, Jun;Yu, Chun;Chi, Lisheng;Sun, Ke
    • Nuclear Engineering and Technology
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    • v.52 no.10
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    • pp.2394-2401
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    • 2020
  • Octadecylamine is an effective film-forming amine that protects carbon steel from corrosion. In the present study, the effect of octadecylamine concentration on adsorption on a carbon steel surface was investigated in anaerobic alkaline solution by using SEM/EDS, TEM and the Materials Studio simulation techniques. TEM morphology observation and EDS elemental detection determine the thicknesses of octadecylamine film on a carbon steel surface, which are confirmed by the in-situ electrochemical impedance spectroscopy measurement and resistance calculation. The Materials Studio simulation reveals the number of octadecylamine film layers at different concentrations. Results obtained in this study indicate that adsorption of octadecylamine film on carbon steel proceeds with the multi-layer adsorption mechanism.

Preparation and Characterization of Pt-Ni Nanocatalyst for Anion Exchange Membrane in Alkaline Electrolysis by Spontaneous Reduction Reaction (자발적 환원반응에 의한 음이온 교환막 수전해용 Pt-Ni 나노 촉매 제조 및 특성)

  • ZHANG, PENGFEI;LEE, JAEYOUNG;LEE, HONGKI
    • Journal of Hydrogen and New Energy
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    • v.33 no.3
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    • pp.202-208
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    • 2022
  • Pt-Ni nanocatalysts were loaded on carbon black by spontaneous reduction reaction of platinum (II) acetylacetonate and nickel (II) acetylacetonate, and they were characterized by transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), energy dispersive x-ray analyzer (EDS), BET surface area and fuel cell test station. The distribution of the Pt and Ni nanoparticles was observed by TEM, and the loading weight of Pt-Ni nanocatalysts on the carbon black was measured by TGA. The elemental ratio of Pt and Ni was estimated by EDS. It was found that the loading weight of Pt-Ni nanoparticles was 5.54 wt%, and the elemental ratio of Pt and Ni was 0.48:0.35. Specific surface area was measured by BET analysis instrument and I-V characteristics were estimated.

Preparation and Characterization of Pt-Fe/Carbon Black Nanocatalyst for Anion Exchange Membrane in Alkaline Electrolysis (음이온 교환막 수전해용 Pt-Fe/카본블랙 나노 촉매 제조 및 특성)

  • SUNGKOOK CHO;JAEYOUNG LEE;HONGKI LEE
    • Journal of Hydrogen and New Energy
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    • v.33 no.6
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    • pp.715-722
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    • 2022
  • Pt-Fe/carbon black nanocatalysts were prepared by spontaneous reduction reaction of Platinum(II) acetylacetonate and Iron(II) acetylacetonate in a nucleophilic solvent and they were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area analysis and anion exchange membrane (AEM) water electrolysis test station. The distribution of the Pt and Fe nanoparticles on carbon black was observed by TEM, and the loading weight of Pt-Fe nanocatalysts on the carbon black was measured by TGA. Elemental ratio of Fe:Pt was estimated by EDS and it was found that elemental ratio of Pt and Fe was changed in the range of 1:0 to 0:1, and the loading weight of Pt-Fe nanoparticles on the carbon black was 5.95-6.78 wt%. Specific surface area was greatly reduced because Pt-Fe nanocatalysts blocked the pores. I-V characteristics were estimated.

Structural Characteristic of One Dimensional Single Crystalline of InN Nanowires (1차원 InN 단결정 나노선의 구조특성에 대한 고찰)

  • Byeun, Yun-Ki;Chung, Yong-Keun;Lee, Sang-Hoon;Choi, Sung-Churl
    • Journal of the Korean Ceramic Society
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    • v.44 no.4 s.299
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    • pp.202-207
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    • 2007
  • High-Quality 1-Dimensional InN single crystalline have been grown by Halide Vapor-Phase Epitaxy on the Au catalyst coated Si substrate using the vapor-liquid-solid growth mechanism. We have been grown 1-dimension InN nanowires having controlled the growth conditions for substrate temperature and gases flow rate. The grown InN nanowire of characteristics for morphologies, crystal structure, and element analysis were carried out by SEM, HR-TEM, and EDS respectively. And the defects of InN crystalline were analyzed by indexing of selective area diffraction pattern with attached HR-TEM. We have successfully obtained the defect-free 1-dimensional InN single crystalline nanowire at the atmosphere pressure.

Physicochemical Characterization of Powder Byproducts Generated from a Metallization Process and Its 1st Scrubber in the Semiconductor Industry (반도체 메탈공정 및 1차 스크러버에서 생성되는 파우더 부산물의 물리화학적 특성분석)

  • Choi, Kwang-Min;Jung, Myung-Koo;An, Hee-Chul
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.25 no.3
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    • pp.294-300
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    • 2015
  • Objectives: The aim of this study is to identify physicochemical properties such as chemical composition, size, shape and crystal structure of powder byproducts generated from a metallization process and its 1st scrubber in the semiconductor industry. Methods: Powder samples were collected from inner chambers during maintenance of the W-plug process equipment (using tungsten hexafluoride as a precursor material) and its 1st scrubber. The chemical composition, size and shape of the powder particles were determined by field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) equipped with an energy dispersive spectroscope (EDS). The crystal structure of the powders was analyzed by X-ray diffraction (XRD). Results: From the SEM-EDS and TEM-EDS analyses, O and W were mainly detected, which indicates the powder byproducts are tungsten trioxide ($WO_3$), whereas Al, F and Ti were detected as low peaks. The powder particles were spherical and nearly spherical, and the particle size collected from the process equipment and its 1st scrubber showed 10-20 nm (agglomerates: 55-90 nm) and 16-20 nm (agglomerates: 80-120 nm) as primary particles, respectively. The XRD patterns of the yellow powder byproducts exhibit five peaks at $23.8^{\circ}$ $33.9^{\circ}$ $41.74^{\circ}$ $48.86^{\circ}$ and $54.78^{\circ}$ which correspond to the (200), (220), (222), (400), and (420) planes of cubic $WO_3$. Conclusions: We elucidated the physicochemical characteristics of the powder byproducts collected from W-plug process equipment and its 1st scrubber. This study should provide useful information for the development of alternative strategies to improve the working environment and workers' health.

A study on the characteristics of double insulating layer (HgCdTe MIS의 이중 절연막 특성에 관한 연구)

  • 정진원
    • Electrical & Electronic Materials
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    • v.9 no.5
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    • pp.463-469
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    • 1996
  • The double insulating layer consisting of anodic oxide and ZnS was formed for HgCdTe metal insulator semiconductor(MIS) structure. ZnS was evaporated on the anodic oxide grown in H$_{2}$O$_{2}$ electrolyte. Recently, this insulating mechanism for HgCdTe MIS has been deeply studied for improving HgCdTe surface passivation. It was found through TEM observation that an interface layer is formed between ZnS and anodic oxide layers for the first time in the study of this area. EDS analysis of chemical compositions using by electron beam of 20.angs. in diameter and XPS depth composition profile indicated strongly that the new interface is composed of ZnO. Also TEM high resolution image showed that the structure of oxide layer has been changed from the amorphous state to the microsrystalline structure of 100.angs. in diameter after the evaporation of ZnS. The double insulating layer with the resistivity of 10$^{10}$ .ohm.cm was estimated to be proper insulating layer of HgCdTe MIS device. The optical reflectance of about 7% in the region of 5.mu.m showed anti-reflection effect of the insulating layer. The measured C-V curve showed the large shoft of flat band voltage due to the high density of fixed oxide charges about 1.2*10$^{12}$ /cm$^{2}$. The oxygen vacancies and possible cationic state of Zn in the anodic oxide layer are estimated to cause this high density of fixed oxide charges.

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